body{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    text-decoration: none;
}

.csdn-header{
    background-color: #fff;
    box-shadow : 0 2px 10px rgba(0,0,0,0.1);
    position: fixed;
    top:0 ;
    width: 100%;
    z-index: 1000;
}
.header-container{
    height: 60px;
    max-width: 100%;
    margin: 0 auto;
    display: flex;
    align-items: center;
    padding: 0 20px;
}
.csdn-logo {
    display: flex;
    justify-content: center;
    margin-right: 20px;
}
.csdn-logo img{
    display: block;
    height: 50px;
    width: 80px;
    vertical-align:middle;
}
.main-menu .nav-list{
    display: flex;
    gap: 25px;
    list-style: none;
    padding-left: 20px;
}

.nav-list a{
    color: #333;
    text-decoration: none;
    font-size: 20px;
    transition: color .2s;
}
.nav-list a:hover{
    color: #FF6A00;
}
.nav-list i{
    margin-right: 5px;
}
.dropdown {
    position: relative;
}
.dropdown-menu {
    width: 68px;
    display: none;
    position: absolute;
    left: -40px;
    list-style: none;
    top: 100%;
    background: #fff;
}
.dropdown:hover .dropdown-menu {
    display: block;
}

/* 搜索框 */
.search-box {
    margin-left: auto; /* 右侧对齐[8,10](@ref) */
    display: flex;
    align-items: center;
}
.search-input {
    padding: 8px 15px;
    border: 1px solid #ddd;
    border-radius: 20px;
    width: 250px;
    outline: none;
    transition: border-color 0.3s;
}
.search-input:focus {
    border-color: #FF6A00; /* 聚焦效果[1](@ref) */
}
.search-btn{
    color: #fff;
    width: 70px;
    height: 30px;
    display: inline-block;
    cursor: pointer;
    border-radius: 16px;
    border: none;
    background-color: rgb(252, 85, 49);
    line-height: 30px;
    transition:  .2s;
}
.search-btn a{
    color: #fff;
    text-decoration: none;

    transition: all 0.3s;
}
.search-btn i{
    display: inline-block;
    width: 24px;
    height: 27px;
    background-image: url("../image/csdn/csdn-white-search.png");
    background-size: 100%;
    vertical-align: middle;
}
.search-btn:hover{
    background-color: rgb(252, 25, 68);

}
.auth-buttons {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: 15px;
    padding-right: 20px;
}

.login-btn {
    color: #FF6A00;
    text-decoration: none;
    font-size: 16px;
    padding: 8px 15px;
    border-radius: 20px;
    transition: all 0.3s;
    border: 1px solid #FF6A00;
}

.register-btn {
    color: #666;
    text-decoration: none;
    font-size: 16px;
    transition: color 0.3s;
}

.divider {
    color: #ddd;
    font-weight: 300;
}

.login-btn:hover {
    background-color: #FF6A00;
    color: white;
    box-shadow: 0 2px 8px rgba(255,106,0,0.3);
}

.register-btn:hover {
    color: #FF6A00;
}
.user-dropdown {
    margin-left:auto;
    position: relative;
    display: inline-block;
    cursor: pointer;
}

.username-trigger {
    padding: 12px 20px;
    background: rgb(255, 255, 255);
    color: black;
    border-radius: 16px;
}

.dropdown-content {
    display: none;
    position: absolute;
    right: 0;
    background: white;
    min-width: 160px;
    box-shadow: 0 8px 16px rgba(0,0,0,0.1);
    z-index: 1;
}

.dropdown-content a {
    display: block;
    padding: 12px 16px;
    color: #2d3748;
    text-decoration: none;
    transition: background 0.3s;
}

.dropdown-content a:hover {
    background: #f7fafc;
}

.user-dropdown:hover .dropdown-content {
    display: block;
}
.search-input{
    margin-right: 10px;
}